Months after diving in Gulf waters fouled by BP crude oil and the oil dispersant Corexit, a man in his 40s has more than five times the normal amount of ethylbenzene in his blood.

The bloodstream of a 3-year-old, exposed to the oil spill when his family visited the Gulf Coast, contains at least three times the normal level of the same organic hydrocarbon, which is toxic in certain quantities.

Such numbers, according to Wilma Subra, a New Iberia biochemist and environmental activist, are increasingly common in a region that continues to grapple with the consequences of the largest oil spill in U.S. history.

And, Subra said Saturday at a forum in New Orleans, they are just one indication that the human health effects of the spill are greater -- and will linger far longer -- than either the oil industry or the U.S. government has acknowledged.

"The effects will be felt for generations," she said, ticking off a wide range of symptoms she said result from exposure to crude oil and Corexit. "This is what we have to look forward to."

Speaking to a receptive audience at the First Unitarian Universalist Church in Uptown, Subra presented data from toxicity tests conducted on humans, Gulf Coast soil and sea life in recent months.

The blood tests were performed on people of varying ages, gender and exposure levels. All of the individuals tested displayed some physical symptoms typical of exposure to crude oil or Corexit, Subra said. Immediate symptoms include skin irritation, nausea, headaches and vomiting. Longer-term maladies can include liver and kidney damage, cardiac arrhythmia and chronic respiratory problems. Benzene also is a cancer-causing agent.

Test results consistently showed elevated levels of chemicals -- among them benzene, ethylbenzene and Xylene -- that are found in either crude, dispersant or both, she said. Results were similar on oysters and other Gulf seafood.

Among soil samples taken in four states, 60 percent showed dangerously elevated levels of petroleum hydrocarbons when compared with normal marine sediment screenings, Subra said.

That, she said, suggests that human and wildlife exposure will continue even after government and industry declare the spill cleaned up.

Subra, who does research for the Louisiana Environmental Action Network, offered a scathing indictment of the way authorities, both public and private, have handled public health issues since the spill.

She said the Occupational Safety and Health Administration, at several points during the oil cleanup last year, issued statements of concern and revised training requirements and safety standards for BP's cleanup workers and volunteers. She said those standards, including the use of biohazard gear, were inadequate and inconsistently enforced, as well as coming after many workers and Gulf Coast residents already were exposed.

Subra said the Food and Drug Administration declared in September that Gulf seafood was free from contaminants, but later modified its statement to state only that the level of toxins found was below levels of danger set by the agency. The problem, Subra said, was the methodology used to set the toxicity threshold. "They said a normal seafood diet would be four jumbo shrimp a week," she said. "How many of you, when you eat jumbo shrimp, only eat four?"

A division of the National Institutes of Health has started a program to track the long-term health effects of the spill. According to an online description, the study began with telephone interviews with more than 55,000 people -- Gulf Coast residents, Coast Guard and National Guard members -- who were involved in the cleanup. The long-term tracking will focus on about 25,000 of them.

Subra said the study, financed in part with $10 million from BP, is fundamentally flawed because it doesn't include the broader Gulf Coast population and, more important, doesn't offer care to those being studied.

Several area residents who attended the forum echoed another of Subra's concerns: Many physicians along the Gulf Coast are reluctant to link their patients' problems to the oil spill or don't have the expertise in environmental medicine to make the connection.

President Barack Obama's National Oil Spill Commission recommended in January that the Environmental Protection Agency establish a more thorough protocol to monitor health effects of major spills.